The present invention relates in general to material handling devices and, more particularly, to a pile stacker for an offset printing press sequentially delivering at its output end printed sheets of paper.
Prior art pile stackers for offset printing presses or the like rely on complex mechanical, electromechanical, or hydraulic mechanisms in an attempt to provide accurate incremental lowering of the sheet-receiving pile stacker table, in accordance with the thickness of the sheets and the rate at which they are being stacked, in order to maintain the top of the stack of sheets at a constant level for the receipt of subsequent sheets fed from a vertically fixed location. The complexity of such mechanisms necessarily leads to high manufacturing costs and reliability problems.
Prior art mechanisms of the subject type are illustrated by the following U.S. Pat. Nos.:
2,795,420 PA1 2,861,805 PA1 3,008,710 PA1 3,516,658 PA1 3,905,595.